Separation of mineral values from ores



Patented Nov. 27, 1945 SEPARATION OF ltgNERAL VALUES FROM RES Frank J. Calm, Chicago, Ill., assignor to The Emulsol Corporation; Chicago, 111., a corporation of Illinois No Drawing. Application April 24, 1941, Serial No. 390,110

16 Claims.

My invention is concerned with the art of separating mineral constituents of ores and the like and is particularly concerned with froth flotation processes.

While the froth flotation process of separating the mineral values from gangue or undesired materials of ores has been quite highly successful in connection with sulphide ores, there is a large number of ores, particularly the non-sulphide ores, in connection with which the results thus far obtained leave much to be desired, not only from the standpoint of operative efliciency but also from the standpoint of reagent cost,

One of the objects of my present invention is to overcome various of the disadvantages which have heretofore attended flotation processes, particularly as regards the treatment of certain classes of ores.

Another object of my invention is the provision of novel flotation reagents.

Another, and important, object of my invention is'concerned with froth flotation processes for separating silica and siliceous materials from ores containing the same, particularly manganese and magnesium ores.

Other objects and features of the invention will become apparent as the description proceeds.

The novel flotation agents which I have found to be particularly suitable for my present purposes are, in general, higher molecularweight aliphatic carboxylic acid esters of hydroxy-alkyl non-tertiary amines, particularly salts, and especially hydrochlorides of said esters, said agents being substantially free of amides of said carboxylic acids with said amines. These novel flotation agents are sharply distinguishable in their structure, their properties and their functioning from such flotation agents as are disclosed, for example, in Patent No. 2,173,909. The flotation agents disclosed in said patent are prepared, for example, by condensing higher molecular weight fatty acids with hydroxy-alkyl amines. Instead of employing the free higher molecular weight fatty acids in the condensation reaction, the corresponding halides, "anhydrides and esters have been suggested. In all of these cases, where the hydroxy-alkyl amine is a primary or secondary amine or, in other words, a non-tertiar amine, the resulting condensation products comprise mixtures of amides and relatively small proportions of esters or mixed ester-amides of the hydroxy-alkyl primary or secondary amines, the amides largely predominating where equi-molal ratios of higher fatty acid and hydroxy-alkylprimary or secondary amine are condensed, and the mixed ester-amides largely predominating where an excess of higher fatty acid or the like isemployed in the condensation reaction. Thus, for example, if monoethanolamine is condensed with an equi-molal amount of lauric acid at elevated temperatures, in excess of degrees C. and particularly at the recommended temperatures of degrees C. to degrees C., or with lauroyl chloride or esters of lauric acid, the resulting condensation products comprise predominantly the lauric acid amide, and relatively small amounts of mixed ester-amide and lauric acid ester of monoethanolamine, which are inextricably mixed with the amide.

I have found, however, that \when higher molecular weight aliphatic carboxylic acid esters of hydroxy-alkyl non-tertiary amines, more particularly the salts of such esters, and especially the hydrochlorides of the esters of hydroxy-alkyl primary amines, are prepared so as to be substantially free of the corresponding amides or mixed ester-amides, they have entirely different flotation properties and characteristics from the condensation products disclosed in the aforementioned patent.

The flotation agents which I emplo herein are prepared in accordance with novel processes since no one, to my knowledge, has suggested any method of producing the same whether for use in the flotation art or for any other purpose. In general, the flotation agents of the present invention may be prepared by reacting a higher molecular weight aliphatic carboxylic acid acyl halide, for example, lauroyl chloride, with an hydroxy-alkyl non-tertiary amine salt, particularly a hydrochloride of an hydroxy-alkyl primary amine such as monoethanolamine hydrochloride.

The reaction is carried out in the presence of a catalyst, particularly an acidic catalyst such as sulphoacetic acid or the like, and preferabl at relatively low temperatures, that is, below 100 degrees C. The ester is recovered in the form of a salt, in the particular illustration given as the hydrochloride of the lauric acid ester of monoethanolamine. i

In order that those skilled in the art may readily and fully understand the nature of the present invention, I shall first describe illustrative examples showing the preparation of the novel flotation agents, and I shall then disclose how such agents may eflectively be utilized in ore separation procedures. With respect to th preparation of the flotation agents, it will be understood that these are merely illustrative and are not to be construed as limitative of the invention in any way. Thus, for example, different combinations of reacting ingredients may b employed, changes may be made in the proportions and temperatures of treatment, such as the use of temperatures of about 50 degrees C. to 60 degrees C. coupled with kneading or vigorous stirring, and other changes may be made, such as the use of acyl bromides instead of acyl chlorides, without departing from the principles of the invention as set out hereinabove and in the appended claims.

ExAnPLs I To 46.1 grams of coconut oil mixed fatty acid acyl chlorides, 0.5 gram of sulphoaceti'c acid was added and there were then added 21.0 grams of the hydrochloride of monoethanolamine. The mixture was heated and stirred at70 degrees C., a violent reaction setting in with evolution of hydrochloric acid. A white, waxy product was obtained consisting primarily of the hydrochloride of the coconut oil mixed fatty acid esters of monoethanolamine. Analysis of said product showed that it contained less than 3% of free gfatty acids and about 101.7% of the theoretical chlorine content, thus showing that the product was quite pure. The product readily dissolved in water to produce a substantially clear solution both in low and in high concentrations.

The coconut oil mixed fatty acid acyl chlorides, used in the example, were prepared in accordance with the method described in my copending application, Serial No. 351,441, filed August 4, 1940. In accordance with that method, coconut oil mixed fatty acids or lauric acid or other higher molecular weight aliphatic carboxylic acids are mixed with phosphorous trichloride in a molal ratio of about one mol of the carboxylic acid to preferably about 50% in excess of mol of phosphorous trichloride. The resulting mixture is heated slowly, while stirring, to about 60 degrees C. to 90 degrees 0., care being exercised to avoid local superheating. The reaction mixture is then allowed to cool to about 40 degrees C. or 50 degrees C. and the lower layer of phosphorous acid is completely drawn off. The upper layer, containing the acyl chloride, is then subjected to a vacuum and a stream of an inert gas such as carbon dioxide is passed through the acyl halide while simultaneously heating at about 130 degrees C. for about one-half hour. This results in removing excess or unreacted phosphorous trichloride and in insuring the preparation of a pure acyl halide. By leaving a small proportion of phosphorous trichloride, for example, about 0.1% to about 0.2%, in the acyl halide product, no extraneous catalyst such as sulphoacetic acid or the like need be employed, the phosphorous trichloride serving to catalytically condition the acylhalide for the reaction.

EXAMPLE II 17.7 grams of the hydrochloride of hydroxyethyl ethylene diamine (HCiH47NHCzH|NH:.H c1) were mixed with 22.0 grams of coconut oil mixed fatty acid acyl chlorides and with 0.6 gram of sulphoacetic acid as a catalyst. The reaction set in at 80 degrees C. and became violent when the temperature was raised to 140 degrees C. The resulting homogeneous product consisted almost entirely of the hydrochloride of the coconut oil mixed fatty acid esters of hydroxy-ethyl ethylene diamine. The product readily dissolved in water to produce a practically clear solution.

The hydrochloride of hydroxy-ethyl ethylene diamine was prepared by adding to 559 grams of concentrated hydrochloric acid 260 grams of hydroxy-ethyl ethylene diamine previously dissolved in 260 cubic centimeters of water. The mass was heated to about degrees C. in vacuo to evaporate the water. The viscous reaction product solidified at room temperature to a hard rock-like substance.

The hydroxy-alkyl non-tertiary amines the esters of which Or the salts of the esters of which comprise the flotation agents of the present invention may be selected from a large group, including symmetrical, unsymmetrical, normal and iso-derivatives, such as monoethanolamine, diethanolamine, mono-propanolamine, dipropanolamine, monobutanolamine, mono-isobutanolamine, monopentanolamine, dibutanolamine, dipentanolamine, monoand di-hexanolamine, monoand di-octanolamine, monoand di-decylolamine, mono-laurylolamine, mono-hexa-decyl olamine, mono-octadecylolamine, mono-ethyl ethanolamine, mono-butyl ethanolamine; arylolamines and cyclic hydroxy amines such as cyclohexyl ethanolamine, N-cyclohexyl butanolamine, ethanolaniline, phenylethanolamine, p-amino phenol,

no-omQ-nm 2-methylamino-propan-diol-1,3; l-phenyl-amino-propan-diol 2,3; l hydroxy ethylamino-2, methoxy-propamol 3; 2 N-methylamino-propandiol-1,3; monoethanol monopropanolamine, monoethanol monobutanclamine, alkylol polyamines such as alkylol derivatives of ethylene diamine, diethylene triamine, and triethylene tetraamine as, for example, hydroxy-ethyl ethylene diamine; diglycerol mono-amine; diglycerol diamine; hydroxy-amines derived from other polyhydric alcohols, including glycols, sugars and sugar alcohols such as ethylene glycol, diethylene glycol, dextrose, sucrose, sorbitol, mannitol and dulcitol;

C2H|OH C:H4NHC1HOH mm-s-mrn-on c,H.-s-o,n.-or1

iH| 2H5 C2HOH and the like; l-amino-2,3-propanediol, 2-amino- 1,3-propanediol; 2-amino-2-methyl-l,3-propanediol; trimethylol amino methane; 2-amino-2-npropyl-l, B-propanediol; 2-amino-2-isopropyl- 1,3-propanediol; Z-amino-Z-methyl-1,4-butanediol; 2-amino-2-methyl-1,5-pentanediol; 2-amino-2-ethyl-1,3-propanediol; 2-amino-2-ethylol- 1,3-propanediol; 2-amino-2-methyl-1,6-hexanediol; 1-amino-l,l-dimethyl ethanol; trimethylol amino-methyl methane; trimethylol aminomethylol methane. The glycerol mono-amines and the related hydroxy amines such as various include hexyl pyridinium chloride, heptyl pyridinium chloride, octyl pyridinium iodide, dodecyl pyridinium bromide, hexadecyl pyridinium iodide, octadecyl pyridinium bromide, dodecyl pyridinium iodide, dodecyl pyridinium chloride, dodccyl-triethyl ammonium iodide,. octyl-triethyl ammonium iodide, decyl-triethyl ammonium iodide, dodecyl-triethyl ammonium iodide, hexadecyl-triethyl ammonium iodide, toluene azophenyl-trimethyl ammonium" iodide, benzene azophenyl-trimethyl ammonium iodide, diphenyl-azophenyl-trimethylammonium methylsulphate, isopropyl-naphthyl-trimethyl ammonium iodide, diethyl-dodecyl sulphonium hydroxide, triethyl-dodecyl phosphonium hydroxide, trimethyl-dodecyl phosphonium iodide, and trimethyl-dodecyl phosphonium bromide.

Where the nonionic or cationic agent is used together with the flotation agents of the present invention, as, for example, the lauric acid ester of monoethanolamine hydrochloride, the best results are, in general, obtained where the nonionic or cationic agent contains an aliphatic or fatty chain of from 6 to 10 carbon atoms, in the usual case preferably 8 carbon atoms, and the monoethanolamine ester or the like contains an aliphatic or fatty chain of from 12 to 18 carbon atoms, particularly 12 to 14 carbon atoms. While the proportions may be varied, the best results are, in general, obtained where the non-ionic or cationic agent is utilized in amounts substantially less than the amount of the monoethanolamine ester or similar flotation agents of the present invention. i

It will be understood, of course, that the various flotation agents, or compositions containing the same, falling with the scope of the invention, will vary in their eflicacy and this variation will also occur with respect to different ores which may be separated by the use thereof. In this same general connection, it will be understood that the optimum proportions of flotation agents, or compositions containing the same, will also be variable although, as a rule, amounts of the order of a few pounds per ton of ore will be utilized. Those skilled in the art will, in the light of my teachings, readily be able to adapt my invention to the treatment of particular ores.

The following examples are illustrative of the practice of my invention asapplied to the flotation of a manganese ore (pyrolusite), the sothe examples are not to be construed as being in any way limitative of the scope of my invention. Thus, for example, various changes may be made with respect to reagent choice, proportions of reagents, selection of particular ores, mesh size of the ore particles, pH of the ore pulp, and the like which will be clear to those versed in the art in the light of the guiding principles disclosed herein.

EXAMPLES called Three Kids ore. It will be understood that to produce a concentrate containing 43.7% manganese from an original head containing about 32% manganese. The percent recovery is the percentage of manganese in the 43.7% manganese concentrate based on all of the manganese introduced into the flotation cell.

In the following tables, reagent A will be used to identify the higher fatty acid ester of monoethanolamine hydrochloride, prepared as described hereinabove, the higher fatty acid being obtained by distilling 100 parts of mixed coconut oil fatty acids and utilizing the first parts which come oil in the distillation. Reagent B will be used to identify the caprylic acid ester of monoethanolamine hydrochloride.

Table I Reagent R Per cent Reagent parts by weight used, emvery' n lb./t. per cent head Reagent A 4. 5 69.3 30. 2 9 parts reagent A+1 part reagent 3.7 82.5 33.8 8 parts reagent A+2 parts reagent B r. 2. 8 79. 5 32. 8 7 parts reagent A+3 parts reagent Table II Reagent Per cent Reagent, parts by weight used, i fggg Mn in lb./t. P head Reagent A 4. 5 69. 3 30. 2 8 parts reagent A+2 parts caprylic acid mono-ester of diethylene glycol 2. 3 77. 3 31. 6 8 parts reagent A+2 parts caprylic acid mono-ester of triethylene glycol 2. l 74. 3 31. 3 8 parts reagent A+2 parts 2-ethyl hexoic acid mono-ester of diethylene glycol 2. 6 77.0 31. 7

In Table III, reagent 0 is the ester of monoethanolamine hydrochloride prepared from what may be characterized as whole coconut oil mixed fatty acids, that is, the mixed fatty acids obtained from coconut oil without distilling off any fraction of said fatty acids.

'Table III Reagent Per cent Reagent, parts by weight used, 3 35? Mn in lb./t. P head Reagent C 6. 7 70.6 33. 3 8 parts reagent 0+2 parts caprylic acid mono-ester of diethylene yc 2. 9 72. 5 34. 3 8 parts reagent 0+2 parts reagent Table IV Reagent Recover Per cent 5, Reagent, parts by weight per cent ltgenniin Reagent A 4. 5 69.3 30. 2 8 parts reagent A+2 parts n-hexyl pyridinium chloride 3. 8 82.0 33. 4

.As indicated hereinabove, the invention is especially useful in connection with the separation of silica and siliceous materials from various ores, particularly by froth flotation although agglomeration methods may also be utilized. In general, a pH of about 7.0 to about 8.5 in the ore pulp is satisfactory. The invention is also highly useful for the separation of the valuable constituents of those disclosed hereinabove may be prepared by various procedures and in different ways. Many of them are conveniently produced by nitrating parailin hydrocarbons, substituting methylol groups for hydrogen on the carbons to which the nitro groups are attached, and then reducing the nitro groups to amine groups. These amine groups may be further alkylated or otherwise substituted it desired. Polymerized hydroxy nontertiary amines or polymerized hydroxy amines containing hydrogen directly attached to nitrogen and prepared, for example, by polymerizing monoethanolamine or diethanolamine or mixtures thereof, or other hydroxy amines such as those mentioned hereinabove, particularly in the presence of a catalyst such as sodium hydroxide or the like, may also be employed. The preparation of polymerized hydroxy amines is disclosed, for example, in United States Patent No. 2,178,173. Homologues and substitution derivatives of the above-mentioned hydroxy amines may also be utilized. Because of commercial and other considerations, monoethanolamine is especially desirable. It will be understood that the hydroxyalkyl primary and secondary amines may be utilized in pure, impure or commercial form,

The higher molecular aliphatic carboxylic acids whose esters or the salts of whose esters comprise the flotation agents of the present invention may also be selected from an extensive group including straight chain and branched chain aliphatic (including cycloaliphatic) carboxylic acids, saturated and unsaturated, such as caprylic acid, capric acid, sebacic acid, behenic acid, arachidic acid, cerotic acid, erucic acid, melissic acid, stearic acid, oleic acid, ricinoleic acid, linoleic acid, linolenic acid, lauric acid, myristic acid, palmitic acid, mixtures of any two or more of the above mentioned acids or other acids, mixed higher fatty acids derived from animal or vegetable sources, for example, lard, coconut oil, rapeseed oil, sesame oil, palm kernel oil, palm oil, olive oil, corn oil, cottonseed oil, sardine oil, tallow, soya bean oil, peanut oil, castor oil, seal oils, whale oil, shark oil, partially or completely hydrogenated animal and vegetable oils such as those mentioned; hydrox-y and alpha-hydroxy higher aliphatic and fatty acids such as i-hydroxy stearic acid, dihydroxystearic acid, alpha-hydroxy stearic acid, alpha-hydroxy palmitic acid, alpha-hydroxy lauric acid, alpha-hydroxy coconut oil mixed fatty acids, and the like; fatty acids derived from various waxes such as beeswax, spermaceti, montan wax, and carnauba wax and carboxylic acids derived, by oxidation and other methods, from petroleum; and cycloaliphatic acids such as naphthenic acid. It will be understood that acyl halides of mixtures of any two or more of said acids may be employed if desired. The acyl chlorides of the unsubstituted fatty acids having from twelve to eighteen carbon atoms are especially satisfactory.

The acids whose salts of the hydroxy-alkyl non-tertiary amines are utilized in the reaction with the carboxylic acid acyl halides to produce the flotation agents include both inorganic and organic acids, but especially satisfactory are the hydrohalic acids, particularly hydrochloric acid and hydrobromic acid, especially the former.

The catalysts may be selected from a large group including, for example, sulphoacetic acid, phosphorous acids, phosphorous trichloride, and the like.

It will be understood that, in thepreparation of the flotation agents, any of the salts of any of the hydroxy-alkyl non-tertiary amines disclosed may be reacted with any of the disclosed aliphatic carboxylic acid acyl halides in the presence of any of the catalysts.

In general, in the preparation of the flotation agents, I prefer to carry out the esteriflcation reaction at a temperature ranging between about.

70 degrees C. and 140 degrees C., at atmospheric pressure. It will be understood, however, that the reaction temperature may be varied and that the reaction may be conducted under sub-atmospheric or superatmospheric pressure if so desired.

I have also discovered that if certain substances, hereinafter described, are utilized together with the flotation agents disclosed hereinabove, there is, in general, a marked improvement in the recovery of desired mineral values and a very definite economy in reagent consumption and, therefore, reagent cost. These addition substances fall into two general categories which may be characterized as (1) certain socalled non-ionic substances, and (2) certain cationic or cation-active substances.

The non-ionic addition substances comprise the aliphatic (including cycloaliphatic) carbox lic acid, particularly fatty acid, partial esters of aliphatic polyhydroxy substances, the aliphatic carboxylic' acid radical containing from 6 to 10 carbon atoms, and preferably from 7 to 9 carbon atoms. Particularly satisfactory are the caprylic and pelargonic acid mono-esters of glycerin and diethylene glycol. Others of the substances of this group are the caproic, enanthic, naphthenic, caprylic, pelargonic, and capric acid partial esters, particularly the mono-esters, of such aliphatic polyhydroxy substances as ethylene glycol, propylene glycol, trirnethylene glycol; polyethylene glycols such as diethylene glycol and triethylene glycol; polyglycerols such as diglycerol, triglycerol, tetra-glycerol and the like including mixtures thereof; carbohydrates, sugars and sugar alcohols such as dextrose, sucrose, xylose, arabinose, fructose, maltose,

dextrins, starches, arabitol, mannitol, sorbitol,

dulcitol, mannitan, sorbitan, and the like.

The cationic or cation-active addition substances comprise a large group and include compounds of aliphatic, carbocyclic, and heterocyclic character in which the surface activity is due to a group or radical present in the cationic portion of the molecule. Among the cation-active compounds which may be employed in accordance with the present invention are the bases or their salts, such as may be derived from pentavalent nitrogen, and further the sulphonium, phosphonium and arsonium, etc. bases and their salts. The quaternary ammonium compounds are examples of satisfactory compounds, the pyridonium or pyridinium compounds being specific examples thereof. In the bases or their salts, the innocuous anions may be hydroxide, chloride, sulphate, bromide, iodide, acetate, etc. The groups inducing cation activity comprise long chain groupings such as aliphatic hydrocarbon chains having from six to eighteen carbon atoms and preferably from 6 to 10 carbon atoms. The long chain groupings may be composed of two or more benzene nuclei or other cyclic radicals, either combined directly or, for example, through carbon or nitrogen or other linkages, with or without aliphatic chains substituted for the hydrogen in rings.

Examples of cation-active substances which may be used in accordance with my invention from the gangue materials in ores or mineral mix tures of various types. Illustrative example of ores which may be treated with satisfactory results in accordance with the teachings of my present invention are, among others, phosphates, such as are present in the non-metallic minerals of th type found in Florida, Tennessee, Idaho, and Montana. feldspars, ilmenite ores, pyroxenes, spinels, picotite, magnetite, micas such as biotite and muscovite. It is definitely preferable initially to deslime the ore pulp prior to carrying out the froth flotation separation treatment, such procedure, among other things, bringing about reduction in reagent consumption. Other ores which may be treated in accordance with the practice of the present invention include chromites, iron ores, lime rock, zirkite, rutile, cassiterite, kaolin minerals, zeolites and similar base exchange material, kyanite, garnet, tourmaline, beryl, fluorspar, and coal. Soluble salt mixtures may also be separated as, for example, sodium chloride and potassium chloride may be separated from each other in a saturated brine made from an ore containing the same, such as sylvinite.

It will also be understood that my novel flotation agents or flotation compositions may be utilized together with one or more already known agents such as collecting agents, frothing agents, depressing agents, emulsifying agents, dispersing agent's, activating agents, deactivating agents. inhibitors, in general, organic and inorganic conditioning agents, and the like. These include, among others, mineral and egetable oils, fuel oil, kerosene, mercaptans, xanthates, organic sulphides, hydrosulphides, carbamates, thio-carbamates, thio-ureas, di-thio-ureas, azo and diaz o compounds, higher molecular 'weight alkyl sulphates such as octyl sulphate, lauryl sulphate, oleyl sulphate, cetyl sulphate, stearyl sulphate, said higher alkyl sulphates being used preferably in the form of their salts such as sodium and the like; alkali metal and heavy metal soaps, higher fatty acids such as oleic acid and palmitic acid, sulphonated oils and sulphonated higher fatty acids such as Turkey red oil and sulphonated oleic acid; gelatin, glue, starch, copper sulphate and other salts of copper, mercury and lead: alkali metal sulphides and fluorides. such as sodium sulphide and sodium fluoride; alkali metal silicates such as sodium silicates; acids such as sulphuric acid, hydrochloric acid and theliker'salts such as potassium ferro-cyanide and other agents which are commonly employed in flotation and agglomeration processes.

The term higher, as used herein and in the claims to describe carboxvlic and fatty acids and the like, will be understood to .mean at least eight carbon atoms unless otherwise specifically stated.

The term esters is used in the claims in a generic sense to include the esters as such as well as the salts of said esters. unless the connotation expressly indicates otherwise.

While the invention has been described in detail, it is to be understood that the scope thereof is not to be limited other than is set forth in the claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. In the process of concentrating ores by froth 7 amine, and subjegtiii he tion separation treatme 1 2. In the process of cd'cen ating ores by froth flotation, the step which comprises adding to the aqueous flotation medium a hydrochloride of a higher molecular weight aliphatic carboxylic acid ester of an hydroxy-alkyl non-tertiary amine, substantially free from amides of said carboxylic acid with said amine, and subjecting the ore to a froth flotation separation treatment.

3. A froth flotation process for the concentration of negatively charged non-sulphide ores which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a salt of a higher molecular weight fatty acid ester of an hydroxyl-alkyl primary amine substantially free from amides of said fatty acid with said amine.

4. A froth flotation process for theconcentration of ores which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a salt of a higher molecular weight fatty acid ester of an hydroxy-alkyl primary amine substantially free from amides of said fatty acid withsaid amine.

" 5. A froth flotation process which comprises agitating and aerating an aqueous suspension of magnesite ore, containing a siliceous gangue, in the presence of a hydrochloride of a lauric acid ester of monoethanolamine substantially free from the lauric acid amide of monoe'thanolamine, and-removing the siliceous gangue in the froth.

6. The process of separating silica or siliceous material from other mineral matter or the like which comprises frothing said mineral matter or which comprises frothing said mineral ,matteror' the like in the presence of an aqueous medium containing a hydrochloride of a lauricacid ester of monoethanolamine substantiallyfree from-the lauric acid amide of monoethanolamine.=

8. The process of separating silica or siliceous material from comminuted ores or the like containing the same which comprises agitating said comminuted ores in an aqueous medium containing a small proportion of a. salt of a higher molecular weightfatty acid ester of an hydroxyalkyl primary amine substantially free -from amides of said fatty, acid with said amine.

' 9. A froth flotation process for the concentration of ores selected from the group consisting of manganese and magnesium ores containing a siliceous gangue, which comprises frothing the are n the-presence of an aqueous medium containing a small proportionof'a hydrochloride of a higher molecular weight aliphatic carboxylic acid ester of an hydroxy-alkyl non-tertiary amine, substantially free from amides of said carboxylic acid with said amine.

10. A froth flotat on process for the concentration of ores selected from the group consisting of manganese and magnesium ores containing a siliceous gangue which comprises frothing the ore in the presence of an aqueous medium fatty acid with said amine, the fatty acid radical containing largely from 12 to 14 carbon atoms.

11. A froth floatation process for the concentration of ores which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a hydrochloride of a higher molecular weight aliphatic carboxylic acid ester of an hydroxy-alkyl'non-tertiary amine, substantially free from amides of said carboxylic acid with said amine, said aqueous medium also containing small proportion of a cationic flotation agent containing a chain of from 6 to 18 carbon atoms.

12. A froth flotation process for the concentration of negatively charged non-sulphide ores which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a hydrochloride of a lauric acid ester of an hydroxy-alkyl primary amine, substantially free from amides of said fatty acid with said amine, said aqueous medium also containing a small proportion of a caprylic acid monoester of an aliphatic polyhydroxy substance selected from the group consisting of glycerine and glycols.

13. A froth flotation process for the concentration of ores selected from the group consisting of manganese and magnesium ores containing a siliceous gangue which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a hydrochloride of the lauric acid ester of monoethanolamine, substantially free from amides of lauric acid with monoethanolamine.

14. A froth flotation process for the concentration of negatively charged non-sulphide ores which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a hydrochloride of an ester of monoethanolamine with mixed higher fatty acids derived from coconut oil and having a predominant content of lauric acid, substantially free from amides of said acids with monoethanolamine, said aqueous medium also containing a relatively small proportion of a caprylic acid mono-ester of an aliphatic polyhydroxy substance selected from the group consisting of glycerin and glycols.

15. A froth flotation process which comprises agitating and aerating an aqueous suspension of an ore, containing a siliceous gangue, in the presence of a hydrochloride of a lauric acid ester of monoethanolamine substantially free from the lauric acid amide of monoethanolamine, and removing the siliceous gangue 'in the froth.

16; A froth flotation process for the concen tration of ores which comprises frothing the ore in the presence of an aqueous medium containing a small proportion of a hydrochloride of a higher molecular weight aliphatic carboxylic acid ester of an hydroxy-alkyl non-tertiary amine, substantially free from amides of said carboxylic acid with said amine, said aqueous medium also containing a small proportion of a partial ester of an aliphatic polyhydroxy substance with an aliphatic acid containing at least 6 carbon atoms.

FRANK J. CAHN. 

